EMI noise issue on PWM input side of motor controller

Thread Starter


Joined Dec 22, 2015
I am making a igbt based motor controller to drive a PMSM. Power inverter was made with 1200V/200A rated IGBTs.
In my assembly, igbt gate drivers were placed close to the power inverter and micro-controller and the other circuits were placed quite away from the drivers (1 to 1.5 feet). 12Vdc, 5Vdc and all pwm signals were connected to gate drivers using twisted wire pairs.
When I turned on pwm signals without giving bus voltage (330Vdc) I could see clean pwm signals, 12V supply and 5V supply. But when I operated inverter with the bus voltage(330Vdc) I saw a huge EMI noise on the system.
I suppressed noises on 12V and 5V supplies using ferrite beads. But ferrite beads did not work for pwm signals. I have attached the oscilloscope images of pwm with induced noises.
Is there any possibility to turn-on and turn-off igbts faulty due to this induced noise notches? How can I filter these EMI noises on PWM signals ?

Thank you